As is well known, in many environments to preserve freshness and inhibit spoiling, foodstuff is often cooled or chilled prior to serving and/or shipping. For example, fishing vessels typically carry refrigeration equipment to allow fish to be chilled as the fish are caught. In this manner, the fish does not spoil and remains edible even over lengthy voyages. Vegetables that are transported by truck or rail are also typically refrigerated during transit to prevent spoiling. Many refrigeration techniques have been employed and include for example, air conditioning units and ice-making machines that produce ice. In the latter case, ice-making machines that produce a slurry of fine ice crystals in a solution have been used to chill food product such as fish and vegetables.
One exemplary type of ice-making machine of this type is disclosed in U.S. Pat. No. 4,796,441 to Goldstein, assigned to the assignee of the subject application, the content of which is incorporated herein by reference. This ice-making machine has a chamber with a fluid inlet to receive a brine solution from which ice is to be made and a fluid outlet to permit the egress of an ice-brine slurry from the chamber. The interior surface of the chamber defines a heat exchange surface. A tubular jacket surrounds the chamber. A refrigerant inlet and a refrigerant outlet communicate with the space between the jacket and chamber and are positioned at opposite ends of the ice-making machine. Refrigerant flowing through the space between the inlet and the outlet boils and in so doing, cools the brine solution in contact with the heat exchange surface. Refrigerant leaving the ice-making machine via the outlet is condensed and compressed before being fed back to the refrigerant inlet. A blade assembly is mounted on a rotatable shaft extending through the center of the chamber and is in contact with the heat exchange surface. A motor rotates the shaft so that the blade assembly removes a cooled layer of brine solution in contact with the heat exchange surface and directs the removed cooled layer into a body of brine solution within the chamber. The shaft is rotated at a rate such that the interval between successive passes of the blade assembly over the heat exchange surface inhibits the formation of ice crystals on the heat exchange surface.
Alternatively, the ice-making machine may be of the type disclosed in U.S. Pat. Nos. 5,884,501, 6,056,046 and 6,286,332 to Goldstein and assigned to the assignee of the subject application, the content of which is incorporated herein by reference. This ice-making machine includes a housing having a brine solution inlet to receive brine solution from which ice is to be made and an ice-brine slurry outlet to permit the egress of an ice-brine slurry from the housing. A heat exchanger within the housing has a heat exchange surface, a refrigerant inlet, a refrigerant outlet and at least one refrigerant circuit interconnecting the refrigerant inlet and the refrigerant outlet. Refrigerant flows through the at least one refrigerant circuit between the refrigerant inlet and the refrigerant outlet to extract heat from the brine solution contacting the heat exchange surface. A blade assembly within the housing carries a plurality of blades, each of which is in contact with the heat exchange surface. The blade assembly is mounted on a shaft, which is rotated by a motor at a rate such that the blades move across the heat exchange surface and remove cooled fluid therefrom thereby to inhibit the deposition of ice crystals on the heat exchange surface.
U.S. Pat. No. 4,936,102 to Goldstein et al., assigned to the assignee of the subject application, discloses an apparatus for cooling fish on board a ship employing for example, an ice-making machine of the type disclosed in aforementioned U.S. Pat. No. 4,796,441. The outlet of the ice-making machine is connected to a pump leading to a flexible hose. The flexible hose can be carried either to a vessel containing salt water or to a catch of fish to direct ice slurry produced by the ice-making machine directly to the catch of fish or to the vessel.
Depending on the product to be cooled and its packaging, delivering ice slurry such as that produced by the ice-making machines described above, can present challenges. For example, it is known to use a manifold to direct an incoming ice slurry to a plurality of stacked, perforated containers simultaneously. For example, FIGS. 1a and 1b show top and side elevational views of such a manifold 100. As can be seen, the manifold 100 is in abutment with one side of a rectangular array of stacked perforated containers 110 that are filled with foodstuff and that rests on a pallet 120. During cooling of the foodstuff in the containers 110, ice slurry is delivered to the inlet of the manifold 100. The ice slurry in turn is discharged by the manifold 100 toward each row of containers 110 via its outlets. Discharged ice slurry in turn enters the containers 110 via the perforations therein. The foodstuff in the containers 110 acts as a filter, trapping ice crystals while allowing the liquid portion of the ice slurry to drain and exit the containers 110 through the perforations. In this manner, the containers 110 become packed with ice crystals. Unfortunately, during this process it is very difficult, if not impossible, to control the amount of ice deposited in each container 110. As each container needs to be packed with ice, this uncertainty can be problematic.
It is therefore an object of the present invention to provide a novel method and apparatus for cooling product.